Tony Forbes writes:
I am looking for odd numbers n (not necessarily prime), n not divisible
by 3, n > 1000 such that both 2^n-1 and 2^n+1 have been completely
factorized into primes.
Look at the factoredM.txt file on my web pages. 2^n + 1 is listed
under 2^(2*n) - 1, from the difference of squares factorization. So,
if there are entries in factoredM.txt for n and 2*n with n odd above
1000, then n meets your criteria.
The Cunningham tables give 1121 and I have been unable to find any more.
However, there has been a lot of recent factorizing activity and my
sources may well be out of date.
I'll say; factoredM.txt has grown _very_ fast lately, I think, though
I haven't actually counted for a while.
I am also interested to know who found the factors 58142098448088409
and 359071640268582342735956401 of 2^1121+1.
It appears that I got them straight from Paul Leyland's Cunningham
Project ftp site; certainly, I don't see, after a few searches in the
appropriate files, email direct to me announcing their discovery.
Will
http://www.garlic.com/~wedgingt/factoredM.txt
